When Lady Macbeth receives Macbeth's news in a letter ... she even takes part in the action. They try to cover up their deed by making it seem as if the King's servants are responsible.

Come, thick night, / And pall thee in the dunnest smoke of hell' Lady Macbeth calls on spirits to bring on night time in order to 'cover up' the murder she is planning. Act 1 Scene 5 'I must ...